The idea of illuminating vehicle wheels or wheel hub caps is well known. The concept stems from safety considerations, more particularly the need to enhance the visibility of trucks and other heavy vehicles when travelling at night. The presence of moving (ie; rotating) lights on a wheel hub cap alerts other road users to the presence of the illuminated vehicle. When vehicles are travelling in close proximity at night, such illumination methods can also warn a driver when they are too close to the side of the illuminated vehicle.
Previous designs of hub cap illumination devices have incorporated an electrical supply powered by the vehicle's internal electrical system. However this necessitates a complicated arrangement of connectors and pick-ups adapted to transmit electrical power through a rotational coupling to the hub. Such a device is complicated and incorporates a number of moving parts. It can therefore be prone to breaking down and the retrofitting of such devices would entail increased cost.
Other methods of powering hub illumination devices include locating batteries within the hub cap itself. The lights powered by such batteries may be activated by centrifugal forces which close a switch and thus complete the illumination circuit.
Clearly this latter method may be deficient in that batteries have a finite lifetime and may be exhausted at inconvenient times and in locations where a replacement battery is not readily available. Also, batteries are a disposable item and this consumption increases the cost of running the vehicle.
While being suitable in some situations, the first embodiment of the present invention can suffer binding when vibrated. Under certain circumstances the first embodiment of the present invention can suffer from the effects of vibration whereby under certain conditions, the rotating shaft on which the coil is mounted interacts with the stationary magnet/weight so that the magnet rotates with the axle thus preventing defeating the induction of currents in the coil. It is believed that this binding or sticking is caused by the rotating parts vibrating under resonance conditions whereby the vibration frequency of the two components is such that the radial component of the force between the axle and the magnet bearing is sufficient to prevent the magnet/weight orienting itself in space (ie; non-rotating in relation to the axle and coil).
Accordingly, it is an object of the invention to provide a wheel/hub cap lighting system which is self-contained, does not require the use of batteries is compact and highly resistant to the effects of vibration and overcomes or at least mitigates some of the above mentioned problems. It is also an object of the invention to provide the public with a useful choice.